CERN Accelerating science

LHCb Note
Report number LHCb-PROC-2022-012 ; CERN-LHCb-PROC-2022-012
Title Fast and flexible data structures for the LHCb Run 3 software trigger
Author(s) Esen, Sevda (University of Zurich (CH)) ; Hennequin, Arthur Marius (Massachusetts Inst. of Technology (US)) ; De Cian, Michel (EPFL - Ecole Polytechnique Federale Lausanne (CH))
Submitted to Connecting The Dots (CTD 2022), Princeton, United States Of America, 31 May - 2 Jun 2022
Submitted by lhcb.secretariat@cern.ch on 05 Aug 2021
Subject category Particle Physics - Experiment
Accelerator/Facility, Experiment CERN LHC ; LHCb
Free keywords LHCb ; Flavour Physics
Abstract Starting in 2022, the upgraded LHCb detector will collect data with a pure software trigger. In its first stage, reducing the rate from 30MHz to about 1MHz, GPUs are used to reconstruct and trigger on B and D meson topologies and high-pTpT objects in the event. In its second stage, a CPU farm is used to reconstruct the full event and perform candidate selections, which are persisted for offline use with an output rate of about 10 GB/s. Fast data processing, flexible and custom-designed data structures tailored for SIMD architectures and efficient storage of the intermediate data at various steps of the processing pipeline onto persistent media, e.g. tapes is essential to guarantee the full physics program of LHCb. In this talk, we will present the event model and data persistency developments for the trigger of LHCb in Run 3. Particular emphasize will be given to the novel software-design aspects with respect to the Run 1+2 data taking, the performance improvements which can be achieved and the experience of restructuring a major part of the reconstruction software in a large HEP experiment.

Email contact(s) : sevda.esen@cern.ch


 Record created 2022-08-05, last modified 2023-07-07


Fulltext:
Download fulltext
PDF

  • Send to ScienceWise.info